The 1985 chlorine and fluorine inventories in the stratosphere based on ATMOS observations at 30° north latitude

The set of high-resolution infrared solar observations made with the Atmospheric Trace Molecule Spectroscopy (ATMOS)-Fourier transform spectrometer from onboard Spacelab 3 (30 April-1 May 1985) has been used to evaluate the total budgets of the odd chlorine and fluorine chemical families in the stratosphere. These budgets are based on volume mixing ratio profiles measured for HCl, HF, CH₃Cl, ClONO₂, CCl₄, CCl₂F₂, CCl₃F, CHClF₂, CF₄, COF₂, and SF₆ near 30° north latitude. When including realistic concentrations for species not measured by ATMOS, i.e., the source gases CH₃CCl₃ and C₂F₃Cl₃ below 25 km, and the reservoirs ClO, HOCl and COFCl between 15 and 40 km (five gases actually measured by other techniques), the 30° N zonal 1985 mean total mixing ratio of chlorine, Cl, was found to be equal to (2.58±0.10) ppbv (parts per billion by volume) throughout the stratosphere, with no significant decrease near the stratopause. The results for total fluorine indicate a slight, but steady, decrease of its volume mixing ratio with increasing altitude, around a mean stratospheric value of (1.15±0.12) ppbv. Both uncertainties correspond to one standard deviation. These mean springtime 1985 stratospheric budgets are commensurate with values reported for the tropospheric Cl and F concentrations in the early 1980s, when allowance is made for the growth rates of their source gases at the ground and the time required for tropospheric air to be transported into the stratosphere. The results are discussed with emphasis on conservation of fluorine and chlorine and the partitioning among source, sink, and reservoir gases throughout the stratosphere.     

National forest carbon inventories: policy needs and assessment capacity

Previous research has identified the importance of the role of land cover in the global carbon cycle. In particular, forests have been identified as a significant carbon sink that can mitigate the rate of global climate change. Policy makers are faced with complex and difficult challenges in getting timely and useful information in monitoring global forest resources. Recent advances in the tools and methods of forest carbon accounting have produced new, innovative approaches to forest-based carbon inventories. But it is important as new tools are developed that scientists understand the needs of policy makers and that policy makers understand the capabilities and limitations of forest inventory methods. This paper explores four different policy applications that rely, or could benefit from, national carbon inventories. The goal is to help build a bridge between the communities of climate policy makers and scientists specialized in forest carbon inventories. To this end, we pursue three specific objectives: First we provide an overview for policy makers about approaches to forest carbon inventories, paying particular attention to the contributions of remote sensing technologies. Second, we outline the issues particularly relevant to forest inventory scientists who are interested in responding to public policy needs. We then discuss the tradeoffs between information cost, accuracy, precision, transparency and timeliness that need to be balanced in long-term monitoring of forest carbon. Finally, the article concludes with a series of observations and recommendations for the implementation of forest carbon inventories as increasingly central components of global climate change policy.     

High latitude river runoff in a doubled CO2 climate

A global atmospheric model is used to calculate the monthly river flow for nine of the world's major high latitude rivers for the present climate and for a doubled CO₂ climate. The model has a horizontal resolution of 4° × 5°, but the model's runoff from each grid box is quartered and added to the appropriate river drainage basin on a 2° × 2.5° resolution. A routing scheme is used to move runoff from a grid box to its neighboring downstream grid box and ultimately to the mouth of the river. In a model simulation in which atmospheric carbon dioxide is doubled, mean annual precipitation and river flow increase for all of these rivers, increased outflow at the river mouths begins earlier in the spring, and the maximum outflow occurs approximately one month sooner due to an earlier snow melt season. In the doubled CO₂ climate, snow mass decreases for the Yukon and Mackenzie rivers in North America and for rivers in northwestern Asia, but snow mass increases for rivers in northeastern Asia.     

Brewer,SAOZ and Ozonesonde Observations in Siberia

Abstract

Regular ground-based measurements of total ozone are available over the full Russian territory using M-124 filter ozonometers, Brewer spectrophotometers, and Système d'Analyse par Observation Zénithale (SAOZ) spectrometers in the Arctic region where these observations are essential for evaluating ozone loss in winter. Daily measurements are performed by three Brewer spectrophotometers; these are located in Kislovodsk (43.7°N, 42.7°E), Obninsk (55.1°N, 36.6°E), and Tomsk (56.5°N, 85.1°E). Two SAOZ spectrometers are deployed at the Arctic Circle in Salekhard (66.5°N, 66.7°E) and Zhigansk (66.8°N, 123.4°E). In addition, regular winter–spring ozonesonde soundings are carried out in Salekhard. Altogether, they have provided the unique measurements over the eastern Arctic required for characterizing ozone loss during each winter and will also monitor the anticipated ozone recovery following the reduction of chlorine and bromine ozone-depleting substances in the atmosphere.     

气象因素对实验室库存物品影响的分析及管理对策

实验室库存物品管理是实验室管理的重要内容,直接关系着实验教学能否顺利进行.分析气象因素对实验室库存物品保存的影响,制定有效的应对方案,对实验室库存物品管理有着十分重要的意义.     

Secular trends in high northern latitude temperature reconstructions based on tree rings

Boreal tree-ring records from high latitude North America, Scandinavia and Russia provide baseline data reflecting long-term trends in Arctic annual temperature. Reconstructions from 1682–1968 indicate the latter part and termination of the Little Ice Age and that the northern regions are now warmer by comparison. The resulting high-resolution, extended temperature time series allows examination of underlying causes of climatic change not possible using only the instrumental record. The recent recorded data for the Arctic show recovery from the cooling in the 1950's–1960's. The overall evaluation confirms that the high northern latitudes are now in an anomalously warm state relative to the past three centuries.     

Dynamic effect of open latitude on wind-driven circulation in a zonal β-plane channel

A class of generalized Fofonoff modes, both barotropic and baroclinic, are found in a β-plane channel presumably to model the circumpolar ocean in the presence of a bottom ridge. These generalized Fofonoff modes share many dynamic features with those in closed basins. Conserved quantities are employed to show that these generalized Fofonoff modes, like those in closed basins, are stable with respect to finite amplitude perturbations.     

Determining Effects of Area Burned and Fire Severity on Carbon Cycling and Emissions in Siberia

The Russian boreal forest contains about 25% of the global terrestrial biomass, and even a higher percentage of the carbon stored in litter and soils. Fire burns large areas annually, much of it in low-severity surface fires – but data on fire area and impacts or extent of varying fire severity are poor. Changes in land use, cover, and disturbance patterns such as those predicted by global climate change models, have the potential to greatly alter current fire regimes in boreal forests and to significantly impact global carbon budgets. The extent and global importance of fires in the boreal zone have often been greatly underestimated. For the 1998 fire season we estimate from remote sensing data that about 13.3 million ha burned in Siberia. This is about 5 times higher than estimates from the Russian Aerial Forest Protection Service (Avialesookhrana) for the same period. We estimate that fires in the Russian boreal forest in 1998 constituted some 14–20% of average annual global carbon emissions from forest fires. Average annual emissions from boreal zone forests may be equivalent to 23–39% of regional fossil fuel emissions in Canada and Russia, respectively. But the lack of accurate data and models introduces large potential errors into these estimates. Improved monitoring and understanding of the landscape extent and severity of fires and effects of fire on carbon storage, air chemistry, vegetation dynamics and structure, and forest health and productivity are essential to provide inputs into global and regional models of carbon cycling and atmospheric chemistry.     

Wildfire Occurrence in Siberia and Seasonal Variations in Heat and Moisture Supply

Subregional occurrence of fires in Siberian forests and seasonal variations in heat and moisture supply are analyzed. Instrumental data on wildfires registered through satellite monitoring data for the period of 1996–2016 are used. The dynamics of the weather fire danger index (PV-1) and intraseasonal anomalies of the Selyaninov’s hydrothermal coefficient (HTC) defining fire occurrence variation are revealed using meteorological data series for the Siberian subregions. The statistical regularities of the dynamics of the weather fire danger index are summarized for subregions. The separated scenarios are formalized by model functions. The projections of the probability of the scenarios’ implementation, the fire return period, and the respective relative burned area are determined.     

Desert heat island study in winter by mobile transect and remote sensing techniques

A familiar problem in urban environments is the urban heat island (UHI), which potentially increases air conditioning demands, raise pollution levels, and could modify precipitation patterns. The magnitude and pattern of UHI effects have been major concerns of a lot of urban environment studies. Typically, research on UHI magnitudes in arid regions (such as Phoenix, AZ, USA) focuses on summer. UHI magnitudes in Phoenix (more than three million population) attain values in excess of 5°C. This study investigated the early winter period—a time when summer potential evapotranspiration >250 mm has diminished to <90 mm. An analysis of the winter magnitude of the heat island in Phoenix has been studied very little, and therefore with the aid of automobile transects, fixed stations, and remote sensing techniques, we investigated a portion of the large Phoenix metropolitan area known as the East Valley. The eastern fringes of the metropolitan area abut against breaks in sloping terrain. The highest UHI intensity observed was >8.0°C, comparable to summertime UHI conditions. Through analysis of the Oke (1998) weather factor Φ_W, it was determined thermally induced nighttime cool drainage winds could account for inflating the UHI magnitude in winter.     

Changes in integral and aerosol atmospheric turbidity in Trans-Baikal and Central Siberia

The analysis of time series of the Linke turbidity factors is performed for the atmosphere mass m = 2 (T ₂) and atmospheric aerosol optical thickness for the wavelength λ₀ = 0.55 μm (AOT) from the data of 14 actinometrical stations of Central Siberia and Trans-Baikal territory. It is shown that over the period from 1976 to 2006, the increased atmospheric transparency is observed in the region. Quantitative estimates of changes in multiyear mean annual variations of T ₂ and AOT at different periods of averaging and for different time periods are derived.     

A mathematical representation of the incident solar energy as a function of latitude and time

A simple mathematical representation of the incoming solar radiation as a function of latitude and time is introduced. The expression approximates the total zonally and daily averaged solar energy incident on the earth's surface before any is absorbed. It includes dependence on both the obliquity and the precession of the equinoxes and, within its accuracy limits, the representation is convenient for use in long-term climate modelling.     

成熟森林生态系统土壤有机碳积累:实现碳中和目标的一条重要途径

为了应对全球气候变化带来的挑战,2020年9月中国提出努力争取在2060年前实现碳中和。对此,生态系统固碳被寄予厚望;然而,生态学理论认为,成熟生态系统的碳输入输出趋于平衡,没有碳的净积累,也就没有碳汇功能,而未成熟的生态系统虽有碳的净积累并具有碳汇功能,但自然界任何未成熟生态系统从它建立的时候开始都在不断地向成熟生态系统演替,即任一生态系统演替的最终结果必然是碳输入输出达到平衡状态。由于森林生态系统碳库是陆地生态系统中最大的碳库,所以人们对其在碳中和上的贡献充满期待。本文以森林生态系统为例,分别考虑森林生态系统碳库的生物量碳库和土壤有机碳库,并基于全球最新研究成果,论证了森林生态系统土壤碳库积累过程具有长久的固碳功能,且不违背成熟生态系统碳输入输出趋于平衡的生态学理论,它能为实现碳中和目标做出贡献。